Lens Driving Actuator

ABSTRACT

According to one embodiment of the present invention, a camera module includes: a movable element having first magnets which are formed at uniform intervals on the outer circumferential surface of a bobbin fixing a lens and second magnets which are arranged between the first magnets on the outer circumferential surface of the bobbin; a stator having first coil blocks which respectively face the first magnets, second magnets which respectively face the second magnets, and a housing which fixes the first coil blocks and the second magnets; an elastic member elastically supporting the movable element with respect to the stator; a base supporting the stator; and a case covering the housing and coupled to the base.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the continuation of U.S. application Ser. No.14/650,476, filed Jun. 8, 2015, which is the U.S. national stageapplication of International Patent Application No. PCT/KR2013/010961,filed Nov. 29, 2013, which claims priority to Korean Application No.10-2012-0145911, filed Dec. 14, 2012, the disclosures of each of whichare incorporated herein by reference in their entirety.

BACKGROUND

Field of the Disclosure

The present disclosure relates to a lens driving actuator configured toadjust a location of a lens with respect to an image sensor.

Discussion of the Related Art

Recently, mobile phones or smart phones, which are installed with acamera module configured to store an object as an image or motionpicture, are being developed.

A conventional camera module includes a lens and an image sensor moduleconfigured to convert light passed through the lens to a digital image.

However, a high-quality digital image can hardly be obtained using theconventional camera module, because the conventional camera module lacksan auto-focusing function to automatically adjust an interval betweenthe lens and the image sensor module. In addition, the conventionalcamera module suffers from a disadvantage in that the image qualitydegradation due to handshake may be cause by the user's handshakes.

BRIEF SUMMARY

According to an exemplary embodiment of the present disclosure, there isprovided a camera module which performs a bi-directional focusingoperation by floating an operator including a lens above a base, as wellas performs a handshake compensation function during the auto-focusingoperation.

Technical tasks of the present disclosure are not limited to theabove-mentioned technical tasks. Other technical tasks which are notmentioned may be clearly understandable for persons who skilled in theart of the present disclosure from the following description.

In a general aspect of the present disclosure, there is provided acamera module, the camera module comprising: an operator including firstmagnets disposed at a bobbin for fixing a lens and second magnetsrespectively arranged between the first magnets; a stator including ahousing having first coil blocks respectively facing the first magnetsand second coil blocks respectively facing the second magnets; anelastic member configured to elastically support the operator withrespect to the stator; a base configured to support the stator; and acase configured to cover the housing and coupled to the base.

According to an exemplary embodiment of the present disclosure, magnetsfor auto focusing and magnets for handshake compensation are alternatelyformed on an outer circumferential surface of the bobbin, and coilblocks disposed at positions responding to the magnets for auto focusingand the magnets for handshake compensation are arranged at the housingof the stator facing the bobbin.

Thereby, the auto-focusing operation and the handshake compensationoperation may be independently performed, or the handshake compensationoperation may be performed during the auto-focusing operation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a camera module according toan exemplary embodiment of the present disclosure.

FIG. 2 is an assembly cross-sectional view of FIG. 1.

FIG. 3 is a selection perspective view illustrating a base, an operator,first coil blocks and second coil blocks of FIG. 1.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments of the present disclosure will bedescribed in detail with reference to the accompanying drawings.

Unless defined otherwise herein, all technical and scientific terms usedherein have the same meaning as commonly understood by one of ordinaryskill in the art to which the present disclosure belongs. In a case whena term used herein conflicts with the customary meaning of thecorresponding term, the meaning of the term defined herein shallsupersede the customary meaning.

However, the inventions mentioned herein are used merely for descriptionof a particular exemplary embodiment of the present disclosure. Thus,they are not intended to limit the scope of the present disclosure.Therefore, the definition of the terms shall be made based on theoverall contents of the present disclosure. The same reference numbersare used throughout the present disclosure to refer to the identicalelements of an exemplary embodiment.

FIG. 1 is an exploded perspective view of a camera module according toan exemplary embodiment of the present disclosure; FIG. 2 is an assemblycross-sectional view of FIG. 1; and FIG. 3 is a selection perspectiveview illustrating a base, an operator, first coil blocks and second coilblocks of FIG. 1.

Referring FIGS. 1 to 3, an actuator (800) according to an exemplaryembodiment of the present may perform an auto-focusing function as wellas a handshake compensation function.

The auto-focus function is a function to drive an operator (100) from astator (200). In order to perform such auto-focus function, the operator(100), which performs a focusing function by being installed with alens, and the base (300) may be spaced from each other when a drivesignal is not applied to the operator (100) and/or the stator (200).

The operator (100) may perform a particular focusing function whilemoving in a fist direction drifting apart from the base (300), accordingas a drive signal for lifting up the operator (100) (such as a forwarddirection current) is applied to the operator (100) floated above thebase (300).

The operator (100) may perform a particular focusing function whilemoving in a second direction approaching to the base (300), according asa drive signal for dropping down the operator (100) (such as a backwarddirection current) is applied to the operator (100) floated above thebase (300).

When moving the operator (100) bi-directionally by applying differentdrive signals to the operator (100) floated with respect to the base(300) on this wise, the consumed current amount may be reduced byreducing the current amount, thereby low power consumptioncharacteristic may be implemented, as well as the time consumed inauto-focusing operation of the operator (100) by reducing drive distanceof the operator (100).

In addition, magnets and coil blocks which perform handshakecompensation function may be arranged at the stator (200) facing theoperator (100). The magnets and the coil blocks may perform thehandshake compensation function along with while the operator (100) isperforming the auto-focus operation.

Hereinafter, a more detailed structure of the actuator (800) havingauto-focusing function and handshake compensation function by suchbi-directional operation will be described.

The actuator (800) may include an operator (100), a stator (200), anelastic member (250), a base (300) and a case (400).

The operator (100) may include a bobbin (110), first magnets (120) andsecond magnets (130). The first magnets (120) may be designed as to beused for implementing the auto-focus function. The second magnets (130)may be designed as to be used for implementing the handshakecompensation function.

The operator (100) may perform the auto-focusing function while movingupward and downward at an upper portion of the based (300), as well asmay perform the handshake compensation function while tilting at anupper portion of the based (300), by interactions with the stator (200)to be described hereinafter.

The bobbin (110) may be formed, for example, in a cylindrical shape. Afemale screw portion to be coupled to the lens (not illustrated in thedrawings) may be formed on an inner circumferential surface of thebobbin (110). Such coupling between the bobbin (110) and the lens may bemade using the female screw portion. Otherwise, the bobbin (110) and thelens may be coupled by a non-threaded coupling using such as anadhesive.

Coupling protrusions (112) to be respectively coupled to the elasticmember (250) (to be described hereinafter) may be formed on the bobbin(110).

The outer circumferential surface of the bobbin (110) may be formed in ashape where curved sections and straight sections are alternatelyformed. Four straight sections and four curved section may be formed onthe outer circumferential surface of the bobbin (110).

Support portions (114) protruded from the outer circumferential surfaceof the bobbin (110) may be formed on lower ends of the four straightsections formed on the outer circumferential surface of the bobbin(110). Recesses (114) concavely recessed from the outer circumferentialsurface of the bobbin (110) may be formed on the four straight sectionsformed on the outer circumferential surface of the bobbin (110). Here,the support portions (114) may be formed on upper ends of the outercircumferential surface of the bobbin (110).

The first magnets (120) may be respectively arranged at the fourstraight sections formed on the outer circumferential surface of thebobbin (110) and may be supported by the support portions (114). Thefirst magnets (120) may be formed in a flat plate magnet. The firstmagnets (120) may be formed in a first size.

In addition, the first magnets (120) may adhere to the outercircumferential surface of the bobbin (110) using such as adhesive.

According to an exemplary embodiment of the present disclosure, thefirst magnets (120) may be formed on the outer circumferential surfaceof the bobbin (110) by a same interval. Four of the first magnets (120)may be arranged on the outer circumferential surface of the bobbin (110)by a 90 degree interval.

The second magnets (130) may be arranged at the recesses (116) formed onthe curved sections of the bobbin (110). Therefore, the second magnets(130) may be arranged between the first magnets (120).

An even number of the second magnets (130) may be formed at a sameinterval between the first magnets (120). For example, the secondmagnets (130) may be respectively arranged between each of the firstmagnets (120). For example, four of the second magnets (130) may beformed.

The second magnets (130) may adhere to the recesses (116) formed on theouter circumferential surface of the bobbin (110) using such asadhesive.

According to an exemplary embodiment of the present disclosure, thesecond magnets (130) may be formed in a second size smaller than thefirst size of the first magnet (120). This is because the amount ofmagnetic force required to implement the auto-focusing function islarger than the amount of magnetic force required to implement thehandshake compensation function, while the area of the outercircumferential surface of the bobbin (110) is restricted.

Of course, the second magnets (130) may be coupled to the straightsections and the first magnets (120) may be coupled to the curvedsections, when the area of the four straight sections on the outercircumferential surface of the bobbin (110) is formed smaller than thearea of the four curved sections.

The stator (200) may include a housing (210), a first coil block (220),a second coil block (230). In addition, the stator (200) may include aterminal pin (240).

The housing (210) may be formed, for example, in a shape of a squarebarrel of which bottom surface is opened. The housing (210) may beformed, for example, by an injection mold process using synthetic resin.

The operator (100) may be arranged in the housing (210). The housing(210) may cover the first magnets (120) and the second magnets (130)arranged on the outer circumferential surface of the bobbin (100) of theoperator (100).

Four side walls (214) forming the housing (210) may be respectivelyformed in a plate shape. A recess for holding the first coil block (220)and the second coil block (230) may be formed on an outer side surfaceof an inner side surface of the side wall (214) of the housing (210).Although it is not illustrated in the drawings, a through-hole forholding the first coil block (220) and the second coil block (230) maybe formed, instead of the recess.

The first coil block (220) may be arranged as facing each of the firstmagnets (120) disposed at the outer circumferential surface of thebobbin (110).

The first coil block (220) may be formed by winding a coil in arectangular shape. The first coil block (220) may be formed in a samesize as the first size of the first magnet (120).

Four of the first coil blocks (220) may be arranged by a same intervalat the housing (210), as four of the first magnets (120) may be arrangedby a same interval at the outer circumferential surface of the bobbin(110).

The auto-focus coil block (220) may generate electromagnetic force by adrive signal. The electromagnetic force generated by the first coilblock (220) may interact with the first magnets (120) and drive theoperator (100) in a direction drifting apart from the base (300), or ina direction approaching to the base (300), respectively.

According to an exemplary embodiment of the present disclosure, one ofboth sockets of the coil block (220) may be mutually and electricallyconnected.

The second coil block (230) may be coupled to the housing (210). Thesecond coil block (230) may be arranged at a position responding to thesecond magnet (130) disposed at the outer circumferential surface of thebobbin (110)

The second coil block (230) may be formed by winding a coil in arectangular shape. The second coil block (230) may be formed in a samesize as the second size of the second magnet (130).

Four of the second coil blocks (230) may be arranged by a same intervalat the housing (210), as four of the second magnets (130) may bearranged by a same interval at the outer circumferential surface of thebobbin (110).

One pair of the second coil blocks (230) arranged as facing each othermay be applied with respectively different drive signals in response toa handshake sensed by a gyro sensor. Thereby the four of the second coilblocks (230) may prevent the handshake.

According to an exemplary embodiment of the present disclosure, thehandshake compensation function by the second magnet (130) and thesecond coil block (230) may be performed after the auto-focusingoperation by the first magnet (120) and the first coil block (110) iscompleted.

Otherwise, the handshake compensation function by the second magnet(130) and the second coil block (230) may be performed while theauto-focusing operation by the first magnet (120) and the first coilblock (110) is being performed.

Meanwhile, terminal pins (240), which apply a drive signal applied fromoutside to the first coil block (220) and the second coil block (230),may be respectively arranged at positions responding to both endportions of the first coil block (220) and both end portions of thesecond coil block (230). The terminal pin (240) may be inserted in thehousing (210).

Each of the first coil block (220) or the second coil block (230) may beformed as a wound coil. Otherwise, each of the first coil block (220) orthe second coil block (230) may be formed as a single coil using FPCB(flexible printed circuit board). Here, the first coil block (220) maybe an auto-focus coil block, and the second coil block (230) may be ahandshake compensation coil block.

The terminal pin (240) may be manufactured in a shape of thin metalplate. A plating layer may be formed on the terminal pin (240), in orderto improve electrical connection characteristic of the terminal pin(240).

Although an exemplary embodiment where the first coil block (220) andthe second coil block (230) may be formed on an outer side surface or anouter side surface of the side wall (214) of the housing (210) is beingillustrated and described, otherwise, a though-hole may be formed on thehousing (210) responding to the first magnet (120).

The base (300) may be formed in a rectangular parallelopipedon. Anopening (305) may be formed on a center portion of the base (300). Acoupling pillar (310) to be coupled to the housing (200) may be upwardlyprotruded on the base (300).

The coupling pillar (310) of the base (300) and the coupling grooveformed on the housing responding to the coupling pillar (310) may becoupled to each other by way of mutual fitting.

An IR filter and an image sensor module may be installed on a rearsurface of the base (300).

A shock absorption member (250) may be arranged on an upper surface ofthe base (300). The shock absorption member (250) may prevent shock fromacting on the operator (100) and the elastic member (250) (to bedescribed hereinafter), when the bobbin (110) of the operator (100)contacts with the base (300).

The shock absorption member (250) may be made of, for example, elasticrubber material, or elastic synthetic resin material.

The case (400) may cover the stator (200) covering the operator (100).The case (400) may prevent the electromagnetic wave generated from thefirst coil block (220) and the handshake compensation coil block (230)of the stator (200) (or the electromagnetic wave from outside) frombeing applied to the first coil block (220) and the handshakecompensation coil block (230).

The case (400) may be formed by press-processing a metal plate, in orderto block foreign matters from outside, as well as in order to block theelectromagnetic wave.

The case (400) may include an upper plate (410) and a side plate (420).The upper plate (410) and the side plate (420) may be integrally formed.

The upper plate (410) may be formed in a shape of rectangular plate whenviewed from a flat side. An opening for exposing the lens fixed to thebobbin (110) of the operator (100) may be formed on a center portion ofthe upper plate (410).

The side plate (420) may extend along an outer side surface of the sidewall (214) of the housing (210) of the stator (200) from an edge of theupper plate (410). The side plate (420) may be fixed to the base (300).

The elastic member (250) may elastically support the operator (100) bybeing coupled to an upper end of the operator (100). The elastic member(250) may elastically support the operator (100) so that the operator(100) can float above the base (300) when a drive signal is not appliedto the operator (100) and/or the stator (200).

Such elastic member (250) may be formed as a plurality of springs orwires connected to an inner side surface of the case (400) and thebobbin (110). As illustrated in the drawings, the elastic member (250)may be formed by press-processing in a shape of leaf spring.

The elastic member (250) may locate the operator (100) as floating abovethe upper surface of the base (300), thereby the operator (100) mayperform the auto-focusing operation or the handshake compensationoperation while being bi-directionally driven with respect to the base(300).

The elastic member (250) may include an upper elastic member (260) and alower elastic member (270).

The upper elastic member (260) may include an inner elastic member(262), an outer elastic member (264) and a connection elastic member(266).

The inner elastic member (262) may be coupled to the coupling protrusion(112) formed on an upper end of the bobbin (110). The inner elasticmember (262) may be formed, for example, in a shape of annular ring.

The outer elastic member (264) may be arranged at an external side ofthe inner elastic member (262). The outer elastic member (264) may beformed, for example, in a shape of rectangular band. The outer elasticmember (264) may be arranged at an upper surface of the housing (210).

The connection elastic member (266) may apply elasticity to the innerelastic member (262) by connecting the inner elastic member (262) andthe outer elastic member (264).

The connection elastic member (266) may be formed in a shape of longband generating elasticity by bending in a zigzag shape. The connectionelastic member (266) may be formed in a symmetrical shape with the innerelastic member (262) as a standard point. Otherwise, the connectionelastic member (266) may be formed in an asymmetrical shape with theinner elastic member (262) as a standard point.

Meanwhile, the lower elastic member (270) may be formed in a shapesimilar to the upper elastic member (260). The lower elastic member(270) may elastically support the bobbin (110) by being coupled to alower surface of the bobbin (110).

According to an exemplary embodiment of the present disclosure, each ofthe connection elastic members (266) of the elastic member (250) mayhave a same elastic modulus. Otherwise, each of the connection elasticmembers (266) of the elastic member (250) may have a different elasticmodulus from one another.

As described in the above with details, the auto-focusing operation andthe handshake compensation operation may be performed independently, orthe handshake compensation operation may be performed during theauto-focusing operation, by forming magnets for auto-focusing andmagnets for handshake compensation alternately at the outercircumferential surface of the bobbin, and by arranging coil blocks atpositions responding to the magnets for auto-focusing and the magnetsfor handshake compensation at the housing of the stator facing thebobbin.

Although descriptions and exemplary embodiments of an actuator aredescribed herein, a camera module may also be formed by combining a lenswith the actuator, and by including an image sensor and a printedcircuit board. Here, the lens may convert an optical signal incidentthrough the lens to an electrical signal. The printed circuit board mayapply electrical power to the actuator. The image sensor may be mountedon the printed circuit board.

In addition, it is obvious that a mobile device (such as mobile phone)including the camera module may be manufactured.

The abovementioned exemplary embodiments are intended to beillustrative, and not to limit the scope of the claims. Manyalternatives, modifications, variations, and equivalents will beapparent to those skilled in the art. The features, structures, methods,and other characteristics of the exemplary embodiments described hereinmay be combined in various ways to obtain additional and/or alternativeexemplary embodiments within an equivalent scope. Therefore, thetechnical scope of the rights for the present disclosure shall bedecided by the claims.

What is claimed is:
 1. A lens driving actuator comprising: a housing; abobbin disposed inside the housing and comprising first to third lateralsurfaces, first corner surface disposed between the first lateralsurface and the second lateral surface and second corner surfacedisposed between the second lateral surface and the third lateralsurface; a first magnet disposed on the first lateral surface of thebobbin; a second magnet disposed on the first corner surface of thebobbin; a third magnet disposed on the second corner surface of thebobbin; a first coil disposed on the housing and facing the firstmagnet; a second coil disposed on the housing and facing the secondmagnet; and a third coil disposed on the housing and facing the thirdmagnet.
 2. The lens driving actuator of claim 1, wherein an outersurface of the second magnet facing the second coil and an outer surfaceof the third magnet facing the third coil are formed as a plane surface,and wherein an imaginary plane surface extended from an outer surface ofthe second magnet is perpendicular to an imaginary plane surfaceextended from an outer surface of the third magnet.
 3. The lens drivingactuator of claim 2, wherein the bobbin is moved along an optical axiswhen power is supplied to the first coil.
 4. The lens driving actuatorof claim 3, wherein the bobbin is moved in a first directionperpendicular to the optical axis when power is supplied to the secondcoil, and wherein the bobbin is moved in a second directionperpendicular to the optical axis and the first direction when power issupplied to the third coil.
 5. The lens driving actuator of claim 3,wherein the bobbin is titled in a first direction perpendicular to theoptical axis when power is supplied to the second coil, and wherein thebobbin is titled in a second direction different from the firstdirection when power is supplied to the third coil.
 6. The lens drivingactuator of claim 2, wherein a length of a long side of an outer surfaceof the first magnet is longer than a length of a long side of the outersurface of the second magnet.
 7. The lens driving actuator of claim 2,wherein an obtuse angle is formed by an imaginary plane surface extendedfrom an outer surface of the first magnet and the imaginary planesurface extended from the outer surface of the second magnet.
 8. Thelens driving actuator of claim 2, wherein each of the first magnet, thesecond magnet and the third magnet is formed as a flat magnet.
 9. Thelens driving actuator of claim 6, wherein the first coil has a flatshape to be parallel with the outer surface of the first magnet and thesecond coil has a flat shape to be parallel with the outer surface ofthe second magnet, and wherein a width of the first coil is larger thana width of the second coil.
 10. The lens driving actuator of claim 2,wherein first magnet is formed as four first magnets disposed by a sameinterval at an outer circumferential surface of the bobbin.
 11. The lensdriving actuator of claim 2, further comprising a base disposed belowthe housing, and wherein a bottom surface of the bobbin is spaced froman upper surface of the base when drive current is not applied to thefirst coil.
 12. The lens driving actuator of claim 11, wherein a shockabsorption member is arranged at the upper surface of the base facingthe bobbin.
 13. The lens driving actuator of claim 2, wherein aplurality of terminal pins coupled with the first coil, the second coiland the third coil are disposed on the housing, and wherein bottom endsof the terminal pins are disposed lower than a bottom surface of thehousing.
 14. The lens driving actuator of claim 2, wherein the elasticmember includes an outer elastic member coupled to the housing, and aninner elastic member coupled to the bobbin, and a connection elasticmember for connecting the outer and the inner elastic members.
 15. Thelens driving actuator of claim 14, wherein a plurality of the connectionelastic members are coupled by a same interval to the outer elasticmember and the inner elastic member, and an elastic modulus of each ofthe connection elastic members is a same.
 16. The lens driving actuatorof claim 14, wherein a plurality of the connection elastic members arecoupled by a same interval to the outer elastic member and the innerelastic member, and the connection elastic members are formed in anasymmetrical shape.
 17. The lens driving actuator of claim 2, whereinthe first coil is formed in a first size, and the second coil is formedin a second size smaller than the first size.
 18. A camera modulecomprising: a printed circuit board coupled with an image sensor; ahousing disposed over the printed circuit board; a bobbin disposedinside the housing and coupled with at least one lens disposed over theimage sensor, wherein the bobbin comprises first to third lateralsurfaces, first corner surface disposed between the first lateralsurface and the second lateral surface and second corner surfacedisposed between the second lateral surface and the third lateralsurface; a first magnet disposed on the first lateral surface of thebobbin; a second magnet disposed on the first corner surface of thebobbin; a third magnet disposed on the second corner surface of thebobbin; a first coil disposed on the housing and facing the firstmagnet; a second coil disposed on the housing and facing the secondmagnet; and a third coil disposed on the housing and facing the thirdmagnet, wherein an outer surface of the second magnet facing the secondcoil and an outer surface of the third magnet facing the third coil areformed as a plane surface, and wherein an imaginary plane surfaceextended from an outer surface of the second magnet is perpendicular toan imaginary plane surface extended from an outer surface of the thirdmagnet.
 19. A mobile phone having a camera module, the camera modulecomprising: a printed circuit board coupled with an image sensor; ahousing disposed over the printed circuit board; a bobbin disposedinside the housing and coupled with at least one lens disposed over theimage sensor, wherein the bobbin comprises first to third lateralsurfaces, first corner surface disposed between the first lateralsurface and the second lateral surface and second corner surfacedisposed between the second lateral surface and the third lateralsurface; a first magnet disposed on the first lateral surface of thebobbin; a second magnet disposed on the first corner surface of thebobbin; a third magnet disposed on the second corner surface of thebobbin; a first coil disposed on the housing and facing the firstmagnet; a second coil disposed on the housing and facing the secondmagnet; and a third coil disposed on the housing and facing the thirdmagnet, wherein an outer surface of the second magnet facing the secondcoil and an outer surface of the third magnet facing the third coil areformed as a plane surface, and wherein an imaginary plane surfaceextended from an outer surface of the second magnet is perpendicular toan imaginary plane surface extended from an outer surface of the thirdmagnet.